Wrench



Sept. 7, 1937.

T. A. KILLMAN ET AL WRENCH Filed March 18, 1936 Patented Sept. 7, 1937 UNIT SAES

Fi t:

WRENCH search Corporation,

Nashville, Tenn.

Application March 18, 1936, Serial No. 69,434

4 Claims.

This invention relates to wrenches having a slidable inner jaw which is advanced to grip the work by means of a hand-grip lever, the latter being operated by the same hand that grasps the shank or handle of the wrench. The hand-grip lever carries pawls which engage a rack on the handle of the wrench.

The invention has for its object to provide a novel and improved wrench of the type stated wherein the teeth of the rack may be made of substantial size but at the same time providing means whereby the movable jaw is advanced toward the stationary jaw with each movement of the hand-grip lever a distance less than that between two adjacent teeth of the rack, thus gaining the advantage of greater gripping power upon the work.

Another object of this invention is to provide a wrenchpf this character wherein by movement of the hand-grip lever thepawls may be entirely disengaged from the rack so that the movable jaw may be slid freely toward or away from the stationary jaw, for preliminary adjustment of the wrench to the approximate size of the work.

Still further and particular objects are to provide a wrench of the type and for the purposes stated which is of extremely simple construction, which is composed of simple and inexpensive parts all capable of being easily and quickly assembled, which has its parts so constructed and arranged as to minimize the opportunity for wear, breakage, and derangement, which is positive and quick in action, which is capable of being marketed at a low cost, and which will prove highly effective in use.

These stated objects and other objects which will incidentally appear in the course of the following description are attained in such a device as is illustrated in the accompanying drawing, and the invention consists in certain novel functions which will be hereinafter first fully described and then particularly pointed out in the appended claims.

In the drawing- Figure 1 is a side elevation of a wrench con structed in accordance with the present inven tion showing the hand-grip lever in its open or ungripped position with the pawls entirely disengaged from the rack. A small section of one side of the hand-grip lever has been cut away in order to more clearly show the position of the pawls;

Figure 2 is a longitudinal section of the same showing the hand-grip lever in its closed or gripped position with one of the pawls in operative engagement with a tooth of the rack;

Figure 3 is a detail transverse section on the line 3-4 of Figure 2.

Referring now in more detail to the drawing the numeral i denotes a shank or handle carrying at one end the fixed jaw member 2 extending on either side of the shank l and provided on one side with a fiat surface 3 and on the other side with a serrated surface t. one edge of the shank l are the teeth 5 forming a rack. A longitudinal slot 6 is cut in the shank as shown.

Loosely encircling the shank and slidable thereon is the sleeve l carrying the movable jaw 8. Movable jaw 3 extends on either side of the sleeve and has formed on one side a fiat surface 9 designed to cooperate with the fiat surface 3 to form a set of jaws for gripping nuts, and other objects having parallel fiat sides. On the other end of the movable jaw member 8 is formed ser- 1 rated surface It! designed to cooperate with the serrated surface 4 to form a set of jaws for holding pipes, rods, and the like.

Pivotally mounted upon the sleeve i by means of the cross rivet ii is the hand-grip lever 52 which is formed of sheet metal into a U-shaped section. The hand-grip lever 62 is designed to partially enclose the shank i when it is in closed or gripped position. Cross rivet i l passes through the longitudinal slot 6 in the shank i thus providing space for movement of the rivet it with the movable jaw member 8 toward and away from the stationary jaw member 2. A flat spring l3 fixed to the hand-grip lever 52 by means of a rivet l3a yieldably urges the hand-grip lever l2 away from shank l toward its fully opened position.

Located within the hand-grip lever l2 are the three rack engaging pawls M, i5, i6, rotatably mounted on rivets I1, l8, and I9 which pass transversely through the hand-grip lever l2. The pawls are provided with tail members Hid, lfia, I60. respectively which are designed to permit only limited rotation of the pawls about their respective pivots.

Flat springs 20 and 2| yieldably urge the pawls to rotate counterclockwise about their pivots. The distance between the center of rotation of adjacent pawls is an integral multiple of the distance between the adjacent teeth of the rack plus one third of the latter distance. Thus it may be seen that only one pawl at a time may be in operative engagement with the teeth of the rack, the other two pawls being withdrawn from Formed along engagement a distance of one third and two thirds of a tooth spacing respectively. The pawls are designed to act as toggle members to force the movable jaw 8 toward the stationary jaw 2 as the hand-grip lever i2 is moved toward the shank l by the grip of one hand of the wrench operator. Thus it may be seen that the arrangement of the pawls and rack form a sort of Vernier rachet toggle wherein each movement of the hand-grip lever l2 from its open to its closed position causes one pawl to advance the movable jaw 8 toward the stationary jaw 2 a distance equal to one third of the rack tooth spacing and the next stroke of the hand-grip lever I2 causes another pawl to advance the movable jaw another one third, and so on.

It is thus obvious that while the teeth of the rack may be made of considerable size in order to gain strength, the movement of the movable jaw for one stroke of the hand-grip lever l2 may be made very small thus increasing the leverage or gripping power of the wrench.

While I have shown in my preferred embodiment three pawls it is of course obvious that a greater or less number may be used without departing from the principle and spirit of the invention.

The movable jaw 8 is provided with an abutment 22 against which the forward end of the hand-grip lever i2 is designed to bear when in its fully open position thus limiting its movement. When hand-grip lever l2 occupies this fully open position the pawls l4, l5, iii are prevented from engaging the teeth 5 of the rack by means of the tail members [4a, Ito, l6a which bear against the under surface of the hand-grip lever 12 and the movable jaw may thus be slid freely toward or away from the stationary jaw.

Various modifications of the arrangements disclosed herein come within the purview of this invention, the scope of which is limited only by the appended claims.

We claim:

1. In a wrench, a shank, teeth upon one face of the shank, a fixed jaw on the shank, a jaw member slidable upon the shank, a hand-grip lever pivotally associated with said slidable jaw, a plurality of pawls pivotally mounted upon said lever and arranged to engage said teeth and to act as toggles to advance the movable jaw toward the fixed jaw upon movement of the hand-grip lever, said pawls being so spaced that only a single pawl at a time may operatively engage said teeth, but other pawls singly operatively engage the teeth upon successive movements of the handgrip lever.

2. A wrench comprising a shank, teeth formed in the shank, a fixed jaw carried by the shank, a movable jaw slidably mounted on the shank, a hand-grip lever pivotally engaged with the movable jaw, a plurality of pawls pivotally mounted upon the hand-grip lever and adapted to engage the teeth formed in the shank and to act as toggle members to advance the movable jaw toward the fixed jaw upon movement of the hand-grip lever, the spacing of the pawls being such that only a single pawl at any one time may operatively engage the teeth, but other pawls operatively engage the teeth singly upon successive movements of the hand-grip lever, means yieldably urging the pawls to rotate about their pivots in a direction to engage the teeth, stops carried by said pawls and adapted to bear against the hand-grip lever for limiting this rotation in such manner that all of said pawls may be entirely removed from engagement with the teeth by extreme movement of the hand-grip lever.

B. A wrench comprising a shank, teeth formed in one face thereof, a fixed jaw carried upon said shank, a movable jaw slidably mounted upon said shank, a hand-grip lever pivotally engaged with the movable jaw, a plurality of pawls pivotally mounted upon the hand-grip lever and adapted to engage the teeth formed in the shank, said pawls designed to act as toggle members to advance the movable jaw toward the stationary jaw when the hand-grip lever is moved toward the shank, the arrangement of the pawls being such that during any single movement of the handgrip lever only a single pawl is operatively engaged with the teeth in the shank and during this single movement of the hand-grip lever said operatively engaged pawl by its toggle action advances the movable jaw toward the stationary jaw a fractional part of the distance between adjacent teeth on the shank, other pawls advancing the movable jaw like distances on successive movements of the hand-grip lever.

4. A wrench comprising a shank, teeth formed in one face thereof, a fixed jaw carried upon said shank, a movable jaw slidably mounted upon said shank, a hand-grip lever pivotally engaged with the movable jaw, three pawls pivotally mounted upon the hand-grip lever and adapted to engage the teeth formed in the shank, said pawls designed to act as toggle members to advance the movable jaw toward the stationary jaw when the hand-grip lever is moved toward the shank, the arrangement of the pawls being such that during any single movement of the hand-grip lever only one pawl is operatively engaged with the teeth in the shank and during this single movement of the hand-grip lever said pawl advances the movable jaw toward the stationary jaw a distance substantially equal to one third the distance between adjacent teeth on the shank, and upon the next succeeding movement of the hand-grip lever a second pawl advances the movable jaw a like distance and so on.

THOMAS A. KILLMAN. ROBERT T. KILLMAN. 

